From: Tomasz Wegrzanowski <taw@...>
Date: 2002-01-03T09:03:38+09:00
Subject: [ruby-talk:30088] Re: mathn questions

On Thu, Jan 03, 2002 at 08:12:58AM +0900, Joel VanderWerf wrote:
> 
> I'm writing some numerical stuff in Ruby and C, and I'd like to use
> mathn.rb for the Ruby part. This is what irb's math mode uses to give
> you '1/2 ==> 1/2' rather than '1/2 ==> 0'. Two questions:
> 
> 1. Does changing integer division in this way interfere with anything in
> the standard library? Any other consequences I should be aware of?
>    The performance cost of using rationals is not a concern to me, even
> considering the garbage creation, since C code is doing all the heavy
> lifting anyway. I just want the Ruby front end to preserve as much
> precision as possible.
> 
> 2. Prime generation seems to happen redundantly in mathn.rb. It looks
> like each time ** or gcd2 is called, the sequence of primes are
> enumerated (partially, of course) *twice*. It would be better to treat
> this sequence as static data and continue the enumeration as needed.
> This is not a big deal for me, just a suggestion for whoever is
> maintaining the code.
> 
> I have the Ruby 1.6.6 version of mathn.rb (which is dated 1998/01/16).

One more advertisement: I made incomplete Ruby bindings to libGMP.
You may consider using this instead of standard Ruby modules.

It supports rational numbers.

See http://freebsd.orzeszkowej.ble.pl/~taw/

Newest version is:
http://freebsd.orzeszkowej.ble.pl/~taw/ruby_gmp.alpha6.tar.bz2